Batteries for hearing aids need to be small in order to fit within the strictly restricted space of a hearing aid housing. Contemporary hearing aids may be powered by a variety of different power sources including, but not limited to, zinc-air batteries, lithium-ion batteries, lithium-polymer batteries and similar compact power sources. Some battery types are disposable, such as zinc-air batteries, while other battery types, such as the lithium-ion or lithium-polymer battery types, are rechargeable. Changing or recharging batteries presents a challenge to a disabled or elderly person due to the small size of the batteries and the motor skills required of the person changing the batteries.
Systems for charging hearing aid batteries while the batteries reside in the hearing aids have been devised, thus eliminating the need for changing batteries. However, the rechargeable batteries of these systems are usually hard-wired into the hearing aids without a possibility for exchanging the battery. This leaves the user with a hearing aid having a useful service life equal to that of the battery itself, e.g. three to four years, leaving the user with no other option but to purchase a new hearing aid once the rechargeable battery is depleted. Since a hearing aid may function reliably for as long as ten years if provided with proper maintenance, this may pose an undue economical burden upon the hearing aid user.